Renewable imaged nonwoven fabric comprising reconstituted fibers

ABSTRACT

The present invention is directed to a nonwoven fabric comprising reconstituted or regenerated fibers (hereinafter referred to as reconstituted fiber or reconstituted fibers), said nonwoven fabric exhibiting improved aesthetic and physical performance, thus permitting use of the fabric in a wide variety of consumer applications. The nonwoven fabric exhibits a three-dimensional image that is durable to both converting and end-use application. In particular, the present invention contemplates that a fabric is formed from a precursor web comprising at least one reconstituted fiber, which when subjected to hydroentanglement on a moveable imaging surface of a three-dimensional image transfer device, an enhanced product is achieved.

TECHNICAL FIELD

[0001] The present invention relates generally to nonwoven fabrics, and more particularly, to a nonwoven fabric comprising reconstituted or regenerated fibers, said nonwoven fabric exhibiting improved aesthetic and physical performance, permitting use of the fabric in a wide variety of consumer applications. The imaged nonwoven fabric is constructed such that durability is imparted by the controlled distribution and variation in fiber density and/or localized basis weight, and can be deconstructed to its component fiber composition and that fibrous component utilized to make new imaged nonwoven fabrics having equivalent aesthetic and/or physical performance.

BACKGROUND OF THE INVENTION

[0002] Nonwoven fabrics are suitable for use in a wide variety of applications where the efficiency with which the fabrics can be manufactured provides a significant economic advantage for these fabrics versus traditional textiles. However, nonwoven fabrics have commonly been disadvantaged when fabric properties are compared to conventional textiles, particularly in terms of resistance to elongation, strength when wetted, and abrasion resistance. Hydroentangled fabrics have been developed with improved properties, by the formation of complex composite structures in order to provide a necessary level of fabric integrity. Subsequent to entanglement, fabric durability has been further enhanced by the application of binder compositions and/or by thermal stabilization of the entangled fibrous matrix.

[0003] More recently, hydroentanglement techniques have been developed which impart images or patterns to the entangled fabric by effecting hydroentanglement on three-dimensional image transfer devices. Such three-dimensional image transfer devices are disclosed in U.S. Pat. No. 5,098,764, which is hereby incorporated by reference; with the use of such image transfer devices being desirable for providing a fabric with enhanced physical properties as well as an aesthetically pleasing appearance.

[0004] Fiber selection for forming hydroentangled nonwoven fabrics are a critical factor when evaluating potential end-use applications. It has been typically found that simple and low cost fibers are unsuitable for fabricating semi-durable or durable end-use articles. In order to improve suitability of such fibers, exogenous binder fibers or other topically-applied adhesive agents have been necessarily incorporated. While a nonwoven fabric embodying such performance improvement means can be employed for semi-durable and durable applications, due to the inherent heterogeneity of the resulting fibrous constructs, such materials can not be readily recycled or reclaimed into equivalent type articles.

[0005] Notwithstanding various attempts in the prior art to develop a nonwoven fabric acceptable for home, medical and hygiene applications, a need continues to exist for a nonwoven fabric comprising simple or basic fibers, which provides a pronounced three-dimensional image, as well as the requisite mechanical characteristics. Further, a need continues to exist for a nonwoven fabric which can be used in semi-durable or durable applications, and yet can be reformed into a newly manufactured nonwoven fabric from waste or used articles comprising such simple or basic fibers, without degradation in aesthetic and/or physical performance of the fabric.

SUMMARY OF THE INVENTION

[0006] The present invention is directed to a nonwoven fabric comprising reconstituted or regenerated fibers (hereinafter referred to as reconstituted fiber or reconstituted fibers), said nonwoven fabric exhibiting improved aesthetic and physical performance, thus permitting use of the fabric in a wide variety of consumer applications. The nonwoven fabric exhibits a three-dimensional image that is durable to both converting and end-use application. In particular, the present invention contemplates that a fabric is formed from a precursor web comprising at least one reconstituted fiber, which when subjected to hydroentanglement on a moveable imaging surface of a three-dimensional image transfer device, an enhanced product is achieved. By specific control of fiber distribution and variation in localized fiber density and/or basis weight, a nonwoven fabric is formed which is resistant to elongation, wet strength failure and degradation due to abrasion, and which does not require further inclusion or application of exogenous binding agents.

[0007] In accordance with the present invention, a method of making a nonwoven fabric embodying the present invention includes the steps of providing a precursor web comprising a fibrous matrix of at least one reconstituted fiber type. While use of natural, finite length fibers may be employed, as exemplified by reconstituted cotton, the fibrous matrix may further include, in part or whole, finite length fibers of synthetic composition. In a particularly preferred form, the fibrous matrix comprises finite length fibers, which are carded to form a precursor web. Optionally, the carded precursor web may be subjected to reorientation, such as by air-randomization or cross-lapping. In one preferred embodiment of the present invention, the precursor web is subjected to pre-entangling on a foraminous-forming surface. Alternately, one or more layers of fibrous matrix, comprising either reconstituted fibers, virgin fibers, or the blends thereof, are juxtaposed with a first reconstituted fiber layer, the layered construct then being pre-entangled on a foraminous surface to form a precursor web.

[0008] The present method further contemplates the provision of a three-dimensional image transfer device having a movable imaging surface. In a typical configuration, the image transfer device may comprise a drum-like apparatus, which is rotatable with respect to one or more hydroentangling manifolds.

[0009] The reconstituted fiber precursor web is advanced onto the imaging surface of the image transfer device. Hydroentanglement of the precursor web is effected to form a three-dimensionally imaged fabric. Significantly, the interaction of a reconstituted fiber exhibiting a prevalence of equal to or less than 10% by weight deleterious fiber artifacts, such fiber artifacts including very short fibers (“fines”) or exceedingly knotted or un-processable fibrous components (“neps”), and a three-dimensional image transfer device allows for the controlled distribution and variation in regional density and/or basis weight of fibers to impart significant and useful durability, without necessarily incorporating exogenous adhesive agents.

[0010] Subsequent to hydroentanglement, the reconstituted imaged fabric may be subjected to one or more variety of post-entanglement treatments. Such treatments may include: application of dyes, printing of patterns or logos, mechanical compaction, application of surfactant or electrostatic compositions, and like processes.

[0011] Other features and advantages of the present invention will become readily apparent from the following detailed description, the accompanying drawings, and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is a schematic drawing of a process by which an image transfer is employed in the manufacture of a nonwoven fabric in accordance with the present invention, and

[0013]FIG. 2 is top plan view of a representative three-dimensional surface topography of an image transfer device, referred to as “small-square”.

DETAILED DESCRIPTION

[0014] While the present invention is susceptible of embodiment in various forms, there is shown in the drawings, and will hereinafter be described, a presently preferred embodiment of the invention, with the understanding that the present disclosure is to be considered as an exemplification of the invention, and is not intended to limit the invention to the specific embodiment illustrated.

[0015] The present invention is directed to a nonwoven fabric comprising reconstituted fibers, said nonwoven fabric exhibiting improved aesthetic and physical performance, permitting use of the fabric in a wide variety of consumer applications. The nonwoven fabric exhibits a three-dimensional image that is durable to both converting and end-use application. In particular, the present invention contemplates that a fabric is formed from a precursor web comprising at least one reconstituted fiber, which when subjected to hydroentanglement on a moveable imaging surface of a three-dimensional image transfer device, an enhanced product is achieved. By specific control of fiber distribution and variation in localized or regional fiber density and/or basis weight. a nonwoven fabric is formed which is resistant to elongation, wet strength failure, and degradation due to abrasion, and which does not require further inclusion or application of exogenous binding or adhesive agents.

[0016] A method of manufacturing a nonwoven fabric embodying the present invention includes the steps of providing a precursor web comprising a fibrous matrix of at least one reconstituted fiber type. While use of natural, finite length fibers may be employed, as exemplified by reconstituted cotton, the fibrous matrix may further include, in part or whole, finite length fibers of synthetic composition. In a particularly preferred form, the fibrous matrix comprises finite length fibers, which are carded to form a precursor web. Optionally, the carded precursor web may be subjected to reorientation, such as by air-randomization or cross-lapping. In one embodiment of the present invention, the precursor web is subjected to pre-entangling on a foraminous-forming surface. Alternately, one or more layers of fibrous matrix, comprising either reconstituted fibers, virgin fibers, or the blends thereof, are juxtaposed with a first reconstituted fiber layer, the layered construct then being pre-entangled on a foraminous surface to form a precursor web.

[0017] It has been found that the interaction of a reconstituted fiber exhibiting a prevalence of equal to or less than 10% by weight deleterious fiber artifacts and a three-dimensional image transfer device allows for the controlled distribution and variation in regional density and/or basis weight of fibers to impart significant and useful durability, without necessarily incorporating exogenous binding or adhesive agents. The formation of suitable and appropriate reconstituted fiber meeting this rate or prevalence is best taught in Pending application Ser. No. 09/755,523, assigned to Environmental Textiles Incorporated, of Oklahoma, and incorporated herein by reference.

[0018] The method of reconstituting fibers, as taught by Pending application Ser. No. 09/755,523, is directed to a sequential process whereby specific mechanisms are employed to “deconstruct” a pre-existing fibrous fabric back into a free-fiber state. In general, pre-existing or pre-formed fibrous fabrics are initially subjected to various means whereby the fabric is reduced to pieces of substantially smaller size and volume. These pieces are then conveyed through, and acted upon, by devices which render-out the fibrous components. The fibrous components are further treated with elevated temperature water vapor and incubation with reducing enzymes, thus removing fiber finishes and other topical additives from the freed fibers. The fibers are then optionally retreated with a new fiber finish, such as an agent to enhance the ability to card such fiber, and are reformed into bales.

[0019] Reconstituted fibers are selected from natural, synthetic, or blended natural/synthetic composition, of homogeneous or mixed finite fiber length. Suitable natural fibers include, but are not limited to, cotton, wood pulp and viscose rayon. Synthetic fibers, which may be blended in whole or part, include thermoplastic and thermoset polymers. Thermoplastic polymers suitable for use as reconstituted fibers include polyolefins, polyamides and polyesters. The thermoplastic polymers may be further selected from; homopolymers, copolymers, conjugates and other derivatives including those thermoplastic polymers having incorporated melt additives or surface-active agents. Finite fiber lengths of the reconstituted fibers are selected in the range of about 0.13 inch to 1.0 inch, the range of 0.25 to 0.75 inches being preferred and the fiber denier selected in the range of 1.0 to 22.0, the range of 1.2 to 6.0 denier being preferred for general applications. The cross-sectional profile of the fiber is not a limitation to the applicability of the present invention.

[0020] With reference to FIG. 1, therein is illustrated an apparatus for forming a nonwoven fabric in accordance with the present invention. The fabric is formed from a fibrous matrix, which typically comprises finite length fibers, of either natural or synthetic composition, or the combinations thereof. The fibrous matrix is preferably carded and optionally cross-lapped to form a fibrous batt, designated F. In a currently preferred embodiment, the fibrous batt comprises 100% cross-lapped fibers, that is, all of the fibers of the web have been formed by cross-lapping a carded web so that the reconstituted fibers are oriented at an angle relative to the machine direction of the resultant web. U.S. Pat. No. 5,475,903, hereby incorporated by reference, illustrates such a web drafting apparatus.

[0021] The apparatus in FIG. 1 includes a foraminous-forming surface in the form of belt 10 upon which the reconstituted fiber precursor web P is positioned for pre-entangling by entangling manifold 12 so as to impart an initial level of working structural integrity to precursor web. Pre-entangling of the precursor web is subsequently effected by movement of the web P sequentially over a drum 14 having a foraminous-forming surface, with entangling manifold 16 effecting entanglement of the web. Further entanglement of the web is effected on the foraminous forming surface of a drum 18 by entanglement manifold 20, with the web subsequently passed over successive foraminous drums 20, for successive entangling treatment by entangling manifolds 24′, 24′.

[0022] The entangling apparatus of FIG. 1 further includes a three-dimensional imaging drum 24 comprising a three-dimensional image transfer device for effecting fiber distribution and localized or regional variations in fiber density and/or basis weight. The image transfer device includes a moveable imaging surface which moves relative to a plurality of entangling manifolds 26 which act in cooperation with three-dimensional elements defined by the topography of the imaging surface of the image transfer device to effect imaging and functional patterning of the fabric being formed. Suitable finishing compositions or the like may be applied at 30, with the fabric dried on suitable drying cans 32.

[0023] Nonwoven fabrics formed in accordance with the present invention have proven to exhibit sufficient resistance to elongation, strength when wetted, and abrasion resistance to warrant use in many end-use applications. Of particular note, the absorbency of nonwoven fabric comprising reconstituted cotton fibers has been sufficiently retained so as to be useful in personal hygiene article and garments, such as make-up removing pads, wash clothes and bathing robes.

[0024] From the foregoing, it will be observed that numerous modifications and variations can be affected without departing from the true spirit and scope of the novel concept of the present invention. It is to be understood that no limitation with respect to the specific embodiments illustrated herein is intended or should be inferred. The disclosure is intended to cover, by the appended claims, all such modifications as fall within the scope of the claims. 

What is claimed is:
 1. A nonwoven fabric comprised of at least one type of reconstituted, finite length fiber, wherein said reconstituted fiber exhibits a prevalence of fibrous artifacts of equal to or less than 10 percent by weight, said reconstituted fiber having been integrated into a nonwoven fabric, wherein said nonwoven fabric has imparted therein regions of differing fiber density and/or basis weight, said nonwoven fabric exhibiting sufficient resistance to elongation, strength when wetted, and abrasion resistance to be usable in durable and semi-durable end-use applications.
 2. A nonwoven fabric as in claim 1, wherein the type of reconstituted, finite length fiber is selected from the group comprising natural fibers, synthetic fibers, and the blends thereof.
 3. A nonwoven fabric as in claim 2, wherein the natural fibers are cotton fibers.
 4. A nonwoven fabric as in claim 2, wherein the synthetic fibers are polyester fibers.
 5. A nonwoven fabric as in claim 1, wherein the reconstituted fiber length is between about 0.13 inches and 1.0 inches.
 6. A nonwoven fabric as in claim 5, wherein the reconstituted fiber length is between about 0.25 inches and 0.75 inches.
 7. A nonwoven fabric as in claim 1, wherein the prevalence of fibrous artifacts is equal to or less than 5 percent by weight.
 8. A nonwoven fabric as in claim 5, wherein the prevalence of fibrous artifacts is equal to or less than 1 percent by weight.
 9. A nonwoven fabric as in claim 1, wherein the nonwoven fabric is integrated by use of hydroentanglement.
 10. A nonwoven fabric comprised of at least one type of reconstituted, finite length fiber, wherein said reconstituted fiber exhibits a prevalence of fibrous artifacts of equal to or less than 10 percent by weight, said reconstituted fiber having been integrated into a nonwoven fabric, wherein said nonwoven fabric has imparted therein regions of differing fiber density and/or basis weight, said nonwoven fabric exhibiting sufficient resistance to elongation, strength when wetted, and abrasion resistance to be usable in durable and semi-durable end-use applications, and wherein said nonwoven fabric can be deconstructed into its fibrous components and reformed to manufacture a new nonwoven fabric of equivalent aesthetic and/or physical performance.
 11. A nonwoven fabric as in claim 10, wherein the same fibrous components can be formed into a nonwoven fabric and subsequently deconstructed for at least 5 cycles. 